1. Field of the Invention
The present invention generally relates to a flywheel assembly, the flywheel assembly having a first flywheel or a first flywheel mass which is detachably connected to the crankshaft of a combustion engine, a second flywheel or a second flywheel mass which can be rotated relative to the first flywheel, and a torque transformer. The torque transformer can be, for example, a hub disc equipped with a torsion damping unit. The flywheel assembly can also include a chamber filled with a viscous medium, which chamber can be located between the two flywheels. The hub disc can be located in this chamber. Further, the chamber can be defined on a side facing the second flywheel by a cover plate, which cover plate defines an air channel between the cover plate and the second flywheel, the air channel extending substantially radially outward from an axial ventilation opening in the second flywheel.
2. Background Information
An example of one such flywheel assembly can be found in German Patent No. 36 30 398 A1, which discloses a flywheel assembly with two flywheels which can be rotated relative to one another. Between the two flywheels there is a hub disc which acts as a torque transformer, on which torque transformer torsion damping units are located. The hub disc rotates in a chamber filled with a viscous medium, and the chamber is defined by the first flywheel and a cover plate fastened to the first flywheel. The cover plate rests with axial prestrees or bias against a seal in the vicinity of the radially inside end of the cover plate, so that the viscous medium is prevented from escaping from the chamber. Further, dust particles, which dust particles are sucked in through a ventilation opening in the second flywheel when the flywheels are spinning, are unable to enter the chamber filled with viscous medium. The air sucked in through the ventilation opening is removed via an air duct which runs radially outward between the cover plate and the second flywheel.
Because the cover plate rests with axial prestress against the seal, relative motion between the two flywheels generally results in friction between the cover plate and the seal, which friction in turn can lead to wear of the seal so that, after a certain amount of wear, the seal can essentially no longer perform its function properly. If the seal is not replaced promptly, the escape of viscous medium from the chamber, and the penetration of dust particles into the chamber, are essentially unavoidable.